This is probably not something to worry
about too much, because I agree with your assessment that this is likely just a muscle pull of the muscles between the ribs or perhaps an inflammation of the joint connecting the sternum to the ribs (called costochondritis). These conditions are quite common and are often associated with vigorous activity.
The pain should get better gradually over several weeks, but it may take a while, especially if you are continuing to exercise vigorously. In order to help it heal up more quickly, you may want to back off on your yoga and other components of your exercise routine. Also standard anti inflammatory medications like ibuprofen or naproxen should be helpful.
Rarely pain after exercise in this area may be a sign of a more serious problem, such as a rib fracture. If the pain is very severe or not starting to improve, you should see your primary care doctor
to rule this out. In addition to a physical exam, your doctor may want to perform an x-ray
of your ribs to make sure that everything is all right.